"Speak to the children of Israel: Tell them to make tassels on the corners of their garments… And you shall have the tassel, that you may look upon it and remember all the commandments of the LORD and do them, and that you may not follow the harlotry to which your own heart and your own eyes are inclined, and that you may remember and do all My commandments, and be holy for your God. I am the LORD your God, who brought you out of the land of Egypt, to be your God: I am the LORD your God."
Numbers 15:38-41

The tassels are not the spiritual point. They were merely reminders of the spiritual point. What was that point?

They and we need to constantly be reminded to follow the Lord. Why? Because our hearts will lead us astray.

The world (and even many well-intentioned Christians) encourage us to “follow our hearts.” That is bad advice—spiritually deadly advice! Why?

Note what God told Moses about the human heart: He said our hearts and eyes are inclined to follow spiritual harlotry (i.e., unfaithfulness to the Lord)!

Jeremiah 17:9 likewise warns us about the human heart: "The heart is deceitful above all things, And desperately wicked; Who can know it?” Do we really want to follow such hearts?

The Israelites wore colored tassels to remind them, to follow the Lord instead of their hearts. We have better reminders. We have the indwelling Holy Spirit, God’s Word, and Christian fellowship, to name only three. Are we looking to these things as reminders?

Israel was to remember that God rescued them from slavery in Egypt. Let us remember the greater deliverance we have in Christ. We have been set free from sin, death, and Hell!